2 Nervous System Physiology Free Online FlashCards

What are the main roles of a neuron's dendrites, cell body, and axon?

Dendrites receive incoming signals, the cell body contains the nucleus, and the axon carries signals away from the cell body.

How does the sodium–potassium pump support a neuron's resting electrical state?

The sodium–potassium pump helps maintain uneven sodium and potassium distributions across the membrane, supporting the neuron's resting voltage difference.

Which ion movements drive depolarization and repolarization in an action potential?

Sodium entry rapidly depolarizes the membrane; potassium exit then repolarizes it.

How can a stronger stimulus affect a neuron's action potentials?

An individual action potential is all-or-none: a stronger stimulus does not make it larger, but may increase how frequently the neuron fires.

How does myelin speed conduction along an axon?

Myelin insulates the axon, and the signal is regenerated at gaps in the covering, enabling rapid saltatory conduction.

What triggers neurotransmitter release at a chemical synapse?

An arriving action potential opens voltage-gated calcium channels; calcium entry triggers neurotransmitter release, and the neurotransmitter binds receptors on the target cell.

How do EPSPs and IPSPs affect a target neuron?

An EPSP moves the target membrane closer to threshold; an IPSP moves it farther away or otherwise reduces the chance of firing.

What distinguishes spatial summation from temporal summation?

Spatial summation combines signals from different locations; temporal summation combines signals arriving close together in time.

What is sensory transduction?

Sensory transduction is the conversion of a physical or chemical stimulus into an electrical signal by a sensory receptor.

How is sensory stimulus intensity commonly encoded?

Stimulus intensity is commonly represented by receptor-potential size and the frequency of action potentials.

Where do afferent sensory signals travel, and where do many pathways relay?

Afferent pathways carry sensory signals into the CNS. Many sensory pathways relay through the thalamus before reaching relevant areas of the cerebral cortex.

Why can a spinal withdrawal reflex occur before conscious perception?

A spinal reflex circuit can produce a rapid motor response from sensory input without waiting for conscious processing, though information can also travel to the brain.